A TIG arc welding tool or a plasma welding tool comprises a head carrying a refractory electrode, such as a rod of non-meltable tungsten, capable of generating an electric arc in association with workpieces to be assembled together so as to form a weld bead between them by melting and mixing their materials.
A laser welding tool comprises a laser generator capable of generating a high energy beam that is applied to the workpieces to form a weld bead between them by melting and mixing their materials.
Such welding tools include means for feeding an inert gas to the head of the tool, the inert gas being for projecting onto the weld bead formed by the molten materials so as to protect said materials against oxidation by the ambient atmosphere.
In order to improve the protection, welders are in the habit of forming a cap of refractory adhesive tape around the welding head in order to confine the inert gas around the weld bead that is being formed and thus improve the quality of the welding.
Such caps are fragile and need to be replaced often, their shapes are not very accurate and poorly adapted to the workpieces, and different from one cap to another, and they are relatively time-consuming to make.